BinaryCacheStore: Optionally write a NAR listing

The store parameter "write-nar-listing=1" will cause BinaryCacheStore
to write a file ‘<store-hash>.ls.xz’ for each ‘<store-hash>.narinfo’
added to the binary cache. This file contains an XZ-compressed JSON
file describing the contents of the NAR, excluding the contents of
regular files.

E.g.

  {
    "version": 1,
    "root": {
      "type": "directory",
      "entries": {
        "lib": {
          "type": "directory",
          "entries": {
            "Mcrt1.o": {
              "type": "regular",
              "size": 1288
            },
            "Scrt1.o": {
              "type": "regular",
              "size": 3920
            },
          }
        }
      }
      ...
    }
  }

(The actual file has no indentation.)

This is intended to speed up the NixOS channels programs index
generator [1], since fetching gazillions of large NARs from
cache.nixos.org is currently a bottleneck for updating the regular
(non-small) channel.

[1] https://github.com/NixOS/nixos-channel-scripts/blob/master/generate-programs-index.cc

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index 38af145f9856..de51716db2ef 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -332,7 +332,7 @@ Path RemoteStore::queryPathFromHashPart(const string & hashPart)
 }
 
 
-void RemoteStore::addToStore(const ValidPathInfo & info, const std::string & nar,
+void RemoteStore::addToStore(const ValidPathInfo & info, const ref<std::string> & nar,
     bool repair, bool dontCheckSigs)
 {
     throw Error("RemoteStore::addToStore() not implemented");